chore(deps): update dependency postcss to v8.5.15

Author: renovate[bot]

package-lock.json

@@ -39,7 +39,7 @@
     "jsdoc": "4.0.5",
     "node-fetch": "3.3.2",
     "npm-run-all2": "8.0.4",
-    "postcss": "8.5.14",
+    "postcss": "8.5.15",
     "webpack": "5.106.2",
     "webpack-cli": "7.0.2",
     "webpack-dev-server": "5.2.4"